Electrical alarm system



(No Model.)

J. P. McMAHON. ELECTRICAL ALARM SYSTEM.

No. 459,591. Patentd S6155. 15, 1891,

Suva whoa NrrEo STATES ATENT OFFICE,

ELECTRICAL ALAFiM SYSTEM.

SPECIFICATION forming part of Letters Patent No. 459,591, datedSeptember 15, 1891. Application filed January 24, 1891 Serial lilo.378,926. (llo model.)

T0 to whom it may concern.-

Be it known that I, JOHN P. MOMAHON, of Jersey City, in the county ofHudson and State of New Jersey, have invented certain new and usefulImprovements in Electrical Alarm Systems, of which the following is aspecification.

The objects of my invention are to simplify and improve electrical alarmsystems such as that described in my patent, No. 416,483, dated December3, 1889, reducing still further the possibility of derangement of thesystem and reducing materially the cost of establishin g the system.

The general objects of the improved system are the same as those of thepreviously patented systemnamely, to indicate the exact location of thefire or other cause of the alarm; toinsure the transmission of thealarm-signal whether the line connecting the building to be protectedwith the central office is broken, grounded, or shortcircuited, andwhether the wires in the building are broken or grounded; to indicate inthe central office the existence of any such trouble with any part ofthe system; to distinguish absolutely between true alarms andtrouble-alarms, and to prevent absolutely the transmission offalsealarms.

The essential parts of the system are, first, a main circuithavingground branches in the protectedbuildiugaudinthecentralofficewithsuitable receiving-instruments, which may be such as those described inmy said patent, in the central office; second, a signal-box located atthe building protected; third, circuit-controllers which may be of thepush-button or other similar type or thermostats, such as are shown inmy said patent; fourth, the system of wires connecting thecircuit-controllers with the signal-box and with the central office.

The present invention relates particularly to the signal-box and itsconnections with the circuit-controllers and the main circuit, and

to the devices in the central office, whereby,

under certain conditions, the battery may be grounded automatically atone end or the other. The signal-box comprises, essentially, a motorwhich may be substantially like the motor described in my said patent,and need not be further described herein, a controllingmagnet therefor,a breaker or breakers actuated thereby, certain other magnets or relays,and a switch. The central-office apparatus comprises, essentially,receiving-id struments in the circuit and a source of electrical supply,such as a battery, other devices being employed for certain purposes, ashereinafter described.

In the accompanying drawings, Figure lis a diagrammatic representationof a complete system,the parts located in the box being inclosed by aheavy dotted line and the system being shown as adapted forabuildingwith but two stories or sections. Fig. 2 is a view of thebreak-wheel audits breakers in proper relation, the same being separatedin Fig. 1 for the sake of clearness; and Fig. 3 is a diagrammaticrepresentien of the devices which may be employed in the central officeto ground the battery at one end or the other when a ground is thrown onthe system by a circuit-controller.

The devices represeutedin Fig. 3 havebeen shown and described bythemselves for the sake of clearness; but it is to be understood that inpractice they take the place of the merely essential instruments in thecentral office. (lndicatedin Fig. 1.)

The receiving-instruments at the central offiee may consist of a relay Rin the main circuit and a relay R in the ground branch, the said branchextending, preferably, from the middle of the battery MB, through thecoils of said relay, and through a switch GS to the ground. The mainline extends from the one pole of the battery to and through everybuilding on the circuit back to the other pole of the battery.

The transmitting device in the box may be constructed substantially asthe corresponding device in my said patent, consisting of a series ofbrushes (1 a a a mounted upon a block of insulating material and restingagainst contacts 0 c c c and a break-wheel adapted to break the contactbetween the brushes and the contacts. The break-wheel is composed of aseries of disks mounted upon a common shaft and insulated from saidshaft and from one another disks of the series are provided with teetharranged in such relation as to indicate the number of the box. Theintermediate disks are provided with teeth to indicate the severalstories'or sections of the buildingj The first and last IOO At eachbuilding the leg 1 of the main line is brought to the binding-post P ofthe signal-box. Thence the circuit is continued by wire 2, brush a ofbreaker A, contact c, wire 3, coils of magnet or relay R, and wire at tobinding-post P From binding-post P it passes by wire 5 through all thestories of the building over the normally-closed contacts m m of all thecircuit-controllers T T back to the box at binding-post P It is thencontinued by wire 6, coils of magnet or relay R wire 7, brush a ofbreaker A contact 0 and wire 8 to binding-post P to which is connectedthe other leg 9 of the main line. So long as the system is in normalcondition a continuous path is thus provided for the current, and therelays R and R are continuously energized and their armatures heldattracted. Any interruption of the continuity of this circuit, whetherby an accidental break in the main line or in the Wire 5 or by theinterruption of the path 5 by the operation of a circuit-controller orby the shortcircuiting of the main line outside of the signal-box, willcause these relays to be de-energized and their armatures to fallagainst their back contacts. This provides a new path for the currentover the coils of the controllingmagnet M, as described below. A wire 11leads from the wire 3 to the back contact 12 of the relay R. From thearmature 13 connection is made by the wire 14 with the coils M of thedifferential controll-ingmagnet M, and thence by wire 15, switch S, Wire16, armature 17 of magnet or relay R its back contact 18, and wire 19 toarmature 23 of relay R back contact 24, wire 25, wire 7, breaker A andwire 8 to binding-post P and the return-leg 9 of the main line. A secondpath is also provided for the current from a point as in wire 15 by wire21, coils M of the differential controlling-magnet M, wire 22, armature23, back contact 24 of relay R wire 25, wire '7, breaker A and wire 8 tobinding-post P and the return-leg 9 of the main line. However, owing tothe resistance offered by the coils M the current will take the pathfirst described and the magnet M will be ener-' gized, the motorreleased, and the box-nu mber will be transmitted to the central office.Upon some moving part of the motor, preferably upon the shaft of thebreak-wheel, is mounted an arm H, which, upon the completion of onerotation of the shaft, is adapted to open the switch S, thereby breakingthe path first above described and compelling the current to take thesecond path over the coils M of the differential controlling-magnet M.This magnetis a differential magnet of usual form and may be composed oftwo coils M and M wound in the same direction upon a common core,whereby when current passes over both coilsin opposite directions themagnet will be neutralized, and when the currentpasses in the samedirection one coil will re-enforce the other. \Vhen, therefore, theswitch S is opened and the current is compelledto take the second pathabove referred to,'the controlling-magnet M is neutralized, its armature released, and the motor stopped after one round of the box-numberhas been sent into the central office. The action just described t-akesplace when the path oltered by the wire 5 is interrupted. If a breakoccurred in the main line outside of the box, no current would pass overthe magnet M and the motor would not be started; but such break would beindicated by a continuous opening of the relay R. If the building wereshortcircuited, the motor would not be started; but the existence of ashort circuit would be indicated by a galvanometer at the central officeby reason of the subtraction from the line of the resistance of thebuilding and the relays in the box. At the same time the system willremain operative under all of these three conditions to transmita truealarm (as distinguished from these trouble-alarms) from acircuit-controller should the occasion therefor arise, as will appearhereinafter. It will also be observed that, notwithstanding a break inthe path 5, the continuity of the circuit is preserved, so that thecondition of one building upon the circuit will not affect theoperativeness of the other boxes on the same circuit. From a point 00 onthe wire 15 runs a Wire 31 through the coils of relay R and having by awire 31 a common connection with one side, as the brushes a a of all thebreakers A A One of these breakers may be provided for each story orsection of the building to be protected and from the other side, as thecontacts a c of each of these breakers runs a wire 32 33 to one side ofthe normally-open contacts at n of the circuit-controllers T or T of thecorresponding story or section of the buildin From the other side of thenormally-open contacts of each group of circuit-controllers (a singlecircuit-controller being represented in the drawings) connection is madeto the ground, as by a wire 34:. The action of a circuit-controller, aswill be understood, is to close the normally-open ground branch,including its respective story-breaker A or A and under certainconditions to throw this ground onto the main line over thecontrolling-magnet, release the motor, and cause the signal to betransmitted to the receiving-instrument in the ground branch at thecentral office, which, signal consists of the box-number, followed bythe story-number, repeated as many times as the break -wheel is allowedto rotate. While the system remains in normal condition this ground willnot be thrown upon the main line, its path being broken between the backcontacts 12 24 and their respective armatures 13 23. The path will becompleted for this ground, however, whenever therelays (either or both)are tie-energized, Whether by a break vin the path 5 or by a break inthe main line or by a short-circuiting of the building. In the firstcase, a break in the path 5 having been indicated previously by oneround of the box, as described, the mag net M will be again energizedanda true alarm will be sent into the central. office. This ground beingcontinuous, the alarm, consisting of the box-number, followed by thestory-number, will be repeated until the motor is stopped, preferably atthe end of the fourth complete rotation of the break-wheel, by some suchmeans as are fully described in my said patent. Thus a true alarm may besent in after a break has occurred in the path 5 and while the breakremains unrepaired, and will be known as a true alarm from the factthatit consists of three full rounds after the one round which indicatedthe break. In the case above described current is compelled, by thebreaking of the path 5, to flow over the coils M of thecontrollingmagnct and so release the motor, the ground having nothing todo with the action until after the completion of the first round. Asbefore described, the switch S is opened and the path 16 broken at thecompletion of the first round, and if the ground is then completed itmust of necessity flow over the coils of the controlling-magnet.Previous to the releasing of the motor, however, the ground, if it cameon under certain conditions, as a break in the leg 1 of the main line,might find a path to the other ground by .Way of the wire 16 withoutpassing over the controlling-magnet. Therefore it is desirable to breakthe path 16 19 whenever one of the normally-open ground. branches in thebuilding is completed. To that end I interpose in the connection betweenthe circuit-controllers and the controlling-magnet a magnet or relay, asR the armature 17 of which, with its back contact 18, (or it might be abreaker actuated by the armature) normally completes the path from Wire16 to wire 19, the said magnet normally having no connection with themain circuit or with the ground. 'As soon as the ground comes on thearmature 17 will be attracted and the possible path 16 19 will bebroken, compelling the ground-current to flow over thecontrolling-magnet. In the event of the building being short-circuitedthe armatures 13 and 23 will fall against their back contacts (therelays being de-energized) and the ground-current coming on, asdescribed,will flow over the coils of the controlling-magnet. The signalthus transmitted will consist of four rounds of the box-number followedby the story-number and will be received upon the receiving-instrumentin the. ground branch at the central ofice. .In the event of a break inthe leg 1 of the main line both armatures 13 and 23 will fall againsttheir back contacts, as before, and the groundof atrue alarm, when thesystem is in normal condition, or of a true alarm following a break inthe path 5, the ground thrownon by a circuit-controller finds currentpassing over both coils of the controlling-magnet in opposite directionsand the said magnet neutralized. In the case of a short-circuiting ofthe building the ground so thrown on finds the current of the main lineflowing over the main line, but shunted from the controlling magnet. Ineither case, under certain conditions, as when the resistance of themain line on one side of the ground is about equal tothe resistance ofthe line on the other side, it is desirable to cause the current to'fiowover one leg only of the main line when the ground is thrown on.Hereinafter I describe certain means for accomplishing thisautomatically; but the same end can be reached by breaking the main linein the central office by a key, as K. The existence of a ground anywhereon the system is made known at the central office by the closing of therelay or the corresponding action of some other receiving-instrument inthe ground branch in the central office. It would therefore be the dutyof the operator in the central office whenever he receives theindication of a ground to open the key K for a moment. If the indicationthereafter received is continuous, he will know that a foreign groundhas been thrown on the system; but if the ground exists on one of thewires 33 in the building the ground-current established by one-half ofthe battery will flow over one coil or the other of thecontrolling-magnet and release the motor, and the current will bealternately broken and completed by the transmitting device, giving acorresponding signal at the central office. The key K, it will beunderstood, is opened only long enough to allow the motor to start. Ifthe ground is thrown on the Wire 33 by the operation of acircuit-controller of the class represented in the drawings, the path 5is broken at the same'time, the armatures of relays R and R fall back,the ground-current continues to IIO pass over the controlling-magnet,and the in othereby the armatures of the relays R and R which fell backwhen the circuit was broken by opening the key, will be attracted, andthe path from the ground in the building to the main line will bebroken. Consequently the motor will stop at the end of the first round,and the fact, as well as the exact location of the accidental ground ona ground branch in a building, willbe indicated at the central office.The signal will be distinguished clearly from that caused by anaccidental break in the'path 5 by reason of the fact that it consists ofthe box-number followed by the storynumber,.while the latter consists ofthe boxnumber alone. Thus it becomes possible at any time to test fromthe central ofiice the condition of the ground branches in thebuildings, for upon the opening of the main circuit at the key a foreignground on any of such branches would at once declare itself.

nates should be indicated visually at the signal-box. To this end I mayinclude in the path from each story-breaker to the ground anannunciator-magnet mm c. WVhen the ground is completed by acircuit-controller,

the armature of this magnet will be held attracted and so indicatevisually the exact location of the cause of the alarm. It is obviousthat each one of such story-magnets might be made to do the work of therelay R and so enable the use of an extra relay to be dispensed with.Normally these storymaguets are not connected with the main circuit orwith the ground.

I have herein indicated the circuit-com trollers as of the kind shown inmy said patent; but it is obvious that the normally-closed contacts andthe normally open contacts might be separately located if convenienceshould render it desirable, the result being the same-namely, to breakthe path 5 and to complete the ground branch at the proper time.

As stated above, it is desirable under certain conditions to ground thebattery at one end or the other when a ground is thrown on by acircuit-controller. To accomplish this automatically is the object ofthe means described below. One end of the battery MB is connected to amovable contact 41, which may be either a pivoted or a spring strip andwhich rests normally against a stop 42, to which is brought the leg 1 ofthe main line. By means hereinafter described the contact 41 may bemoved to a stop 43, which is connected by Wire 44 With-the ground G Theother end of thebattery has similar connections over contact 45 and stop46 with the leg 9 of the main line or by stop 47 and wire 48 'tery willbe thrown on the other.

with the ground G The common ground branch may include areceiving-instrument R The ground branch from the middle of thebatteryincludes a switch GS and a magnet, preferably in the form of adifferential galvanometer or other equivalent device G It then passes bywire 51 to movable contact 52, stop 53, wire 54 stop 55, movable contact56, and wire 57 to the ground G. The movable contacts 41 56 are actuatedor released by a drop 40, as indicated, and the contacts 45 52 by a drop49. The said drops are under the control, respectively, of the magnets mand on. The galvanometer-needle 60 is connected with one end of thebattery GB.

Thence connection is made by wire 61 through the coils of the magnet mwith the stop 62 for the end of the needle. Connection is also made bywire 63 through the coils of the magnet m with the other stop 64 for theend of the needle. WVhen there is no ground upon the system other thanthe office ground G, the galvanometer is not affected; but if anotherground is thrown on it will take the shortest path to the office groundover one half or the other of the battery MB. The needle will then bedeflected to one side or the ether, completing the circuit throughmagnet m or m and releasing the corresponding drop. The effect of this,as will be seenreadily, will be to break the ground from the middle ofthe battery at the point 53 or 55, to break the main line at the point42or 46,and to connect the other end of the battery with the ground fromthe point 43 or 47. Thus, if the leg 9 of the main line be broken and aground the corresponding end of the battery, and the battery will bethrown on the leg 1 of-the main line. In case of a short-circuiting of abuilding the ground subsequently thrown on by a circuit-controller willtake the path of least resistance to the office ground, the galvanometerwill be deflected, and one leg of the main line will be broken, whilethe bat- VVhen a foreign ground occurs, indicated by continuous actionof the receiving-instrument in the ground branch, the office ground isdisconnected and the system operates as described in my said patent forlike conditions.

It may be desirable to leave the breaking of the main circuit to be doneby the operator rather than automatically, as described above. In thatcase the two legs of the main circuit, after passing through the relaysRR, are connected directly to the poles of the battery over keys K andK, as indicated by dotted lines in Fig. 3.

I claim,

ers, a controlling-magnet therefor, a connection between one side of allof said breakers therefor, a connection between one side of all of saidbreakers and said circuit, said connection including said magnet, aseparate ground branch from the other side of said breakers, and acircuit-controller in each of said ground branches, substantially asdescribed.

3. The combination of a main circuit, a ground branch therefrom, atransmitting device comprising a series of breakers, there being onebreaker in each leg of said circuit and the intermediate breakers beingconnectedon one side to said circuit between the two breakers firstreferred to, and a separate ground branch from the other side of saidintermediate breakers, substantially as described.

4. The combination of a main circuit, a ground branch therefrom, atransmitting device comprising a series of breakers, there being onebreaker in each leg of said circuit, and the intermediate breakers beingconnected on one side to said circuit between the two breakers firstreferred to, a separate ground branch from the other side of saidintermediate breakers, and a circuit-controllerin each of saidlast-named branches, substantially as described.

5. The combination ofa main circuit, a n10- tor, a differentialcontrolling-magnet, a shunt from one leg of said circuit to the other,including one member of said magnet, a switch in said shunt, adapted tobe opened by said motor, and a path from said shunt between the magnetand the switch to said other leg of the main circuit and including theother member of said magnet, substantially as described.

6. The combination of a closed metallic circuit including a battery, aground branch from said battery, a differential magnet having both itsmembers included in the circuit with said battery, a normally openground branch from a point on said circuit between the members of saidmagnet, and a circuitcontroller in said branch, substantially asdescribed.

7. The combination of a metallic circuit, a ground branch therefrom, acircuit-breaker therein, a motor for actuating said breaker, adifferential controlling-magnet for said motor, having both its membersincluded in said circuit, and a normally-open ground branch from saidcircuit between the members of said magnet, substantially as described.

8. The combination of a metallic circuit, a ground branch therefrom, adifferential magnet having both its members included in said circuit, anormally-open ground branch from said circuit between the members ofsaid magnet, a circuit-breaker in said branch, and a motor for actuatingsaid breaker, controlled by said magnet, substantially as described.

0. The combination of a main circuit, a ground branch therefrom, adifferential magnet, a shunt from one leg of said main circuit to theother, including one member of'said magnet, a circuit-breaker in saidshunt, a path from said shunt between the magnet andthe circuit-b reakerto said other leg of the main circuit and including the other member ofsaid magnet, and a ground branch between the members of said magnet,including a relay adapted to operate said circuit-breaker,

substantially as described.

10. The combination of a main circuit, a transmitting device and itsmotor, a controlling-magnet therefor, a relay, as R, in said 11. Thecombination of a main circuit,

transmitting device and its motor, a controlling-magnet therefor, arelay, as R, in said circuit, contacts controlled by said relay,connections from one of said contacts to said circuit on one side ofsaid relay and frointhe other of said contacts to said circuit on theother side ofsaid relay, said connections including acontrolling-magnet, and a switch adapted to be shifted by said motor,substantially as described.

12. The combination of a main circuit, a ground branch therefrom, atransmitting device, a controlling-magnet therefor, a relay, as R, insaid circuit, contacts controlled by said relay, connections from onecontact to said circuit on one side of said relay and from the othercontact to said circuit on the other side of said relay, and includingsaid controlling-magnet, and a branch from said last-named connection tothe ground, substantially as described.

13. The combination of the main line, a ground branch therefrom, abuilding-wire, as 5, includingaseries of closed-contactcircuitcontrollers, a magnet, as R, in the connection between said mainline and buildingwire, a normally-open branch from said main line on oneside of said series of circuit-controllers to said main line on theother side thereof, a ground connection including a circuit -controllerfrom said normallyopen branch, and meanscontrolled by said magnet toclose said normally-open branch, substantially as described.

14. The combination of the main line, a building -wire, as 5, includinga series of closed-contact circuit-controllers, a magnet, as R, in theconnection between said main line and said building-wire, anormally-open branch from said main line on one side of said series ofcircuit-controllers tosaid main line on the other side thereof, amagnet, as

M, in said branch, and means controlled by said first-nained magnet toclose said branch, substantially as described.

15. The combination of a main circuit, a signaling mechanism, adifferential controlling-magnet for said mechanism included in saidcircuit, a normally-open ground branch from said circuit between themembers of said magnet, a battery in said circuit, a movable contact andstop therefor, onebeing connected to one end of said battery and theother to the ground, a ground branch from said battery, a magnetincluded in said branch, and means controlled by said magnet to shiftthe movable contact to said stop, substantially as described.

16. The combination of a main circuit including a battery, a movablecontact and stop therefor,onebeing connected toone end ofsaid batteryand the other to the ground, a ground branch from said circuitincludinga movable contact, a magnet in said ground branch, and meanscontrolled by said magnet to shift the first-named contact to saidgrounded stop and to shift the second-named contact to break themagnetground, substantially as described.

17. The combination of a main circuit, a signaling mechanism, adifferential controlling-magnet for said mechanism included in saidcircuit, a normally-open ground branch from said circuit between themembersof said magnet, a battery in said circuit, a movable said groundbranch, and means controlled by said magnet to close one or the other ofsaid normally-open grounds, substantially as described.

19. The combination of a main circuit including a battery, a movablecontact in the connection between each end of the battery and the mainline, a grounded stop for each contact, a ground branch from the middleof the battery, a magnet in said ground branch, a movable contact insaid ground-branch cor- I responding to each of said first-named movablecontacts, and means controlled by said magnet to shift one set or theother of said contacts, substantially as described.

In witness whereof I have hereunto set my hand.

JOHN P. vMcMAHON. Witnesses:

GEORGE DANA WHITE, EDWARD A. GREELEY.

